Traditionally, aircraft communications have been between ground stations and the aircraft, or between two adjacent aircraft. Ground communications may be interrupted for various reasons, and more recently communications links have been developed between orbiting satellites and aircraft. Transmissions between communications satellites in geostationary or geosynchronous (geostationary/geosynchronous) orbit and aircraft in flight are becoming increasingly important. Transmitted information can include, for example, internet uplinks and downlinks, audio and video entertainment, business information, and information relevant to the aircraft's flight operations such as weather and navigation data.
Maintaining a robust, uninterrupted communications link between an aircraft in flight and a geosynchronous/geostationary satellite is a challenging geometric problem. Geostationary satellites, to cite an example, are in orbit above a fixed position on the equator. When an aircraft is flying in straight-and-level flight near the equator, the linked geostationary satellite is usually at a relatively high elevational angle from the aircraft. On the other hand, when the aircraft is flying at a high latitude, the geostationary satellite is typically at a much lower elevational angle relative to the aircraft. The elevation and azimuth of the geostationary satellite relative to the aircraft also change as the aircraft banks, changes its direction of flight, and climbs or descends.
To facilitate communication links at various positions of the aircraft over the earth, large aircraft typically utilize tracking dish antennas or the like. A steerable dish antenna may be mounted, for example, in a radome on the top of the vertical tail. As the aircraft flies, the elevation and azimuth of the steerable dish antenna are adjusted as needed to point toward the linked satellite. However, steerable dish antennas are too bulky, heavy, and expensive for many smaller aircraft, such as most business and private aircraft.
There is a need for an aircraft-mounted approach that provides a robust communications link between the aircraft and a satellite or other airborne transceiver, for virtually all normally encountered locations, flight paths, and flight attitudes of the aircraft. The present invention fulfills this need, and further provides related advantages.